This invention relates to swimming goggles used by swimmers or divers.
Japanese Utility Model Registration Gazette No. 2570206 discloses swimming goggles in which an elastic head strap made of rubber has its opposite free ends guided through strap guiding holes provided at outer ends of respective lens frames from the rear toward the front so that the head strap can be fastened around a goggles' wearer. These free ends are then folded twice or more along supports provided on the outer ends of the respective lens members and thereafter guided through the strap guiding holes from the front toward the rear. Within the strap guiding holes, two sections of the strap are placed against each other and thereby frictionally restrict a relative movement of these two sections. In this manner, the strap is prevented from falling off from the strap guiding holes even when the strap is fastened around the wearer's head and pulled rearward. Thus the head strap is adjusted to a desired length relative to the swimming goggles.
However, the known swimming goggles are not free from a problem such that the free ends of the strap which have been guided through the strap guiding holes may be moved little by little in a direction of falling off every time the head strap contracts during its repeated expansion and contraction. Consequently, after the swimming goggles have been repeatedly put on and taken off, the head strap once adjusted to the optimum length for fitness around the wearer' head may slacken. To correct such inconvenient situation, the length of the head strap must be often readjusted. Certainly, it is possible to inhibit the undesired movement of the free ends by forcibly inserting wedge-like stopper members between peripheral edges of the respective strap guiding holes and the free ends guided through the strap guiding holes, respectively. However, the strap becomes thinner as the strap is stretched and the effect of the stopper members is correspondingly deteriorated and therefore the length of the strap must be readjusted in this case also when the swimming goggles are used for a long period.